The Broken Promise
by AskEmily94
Summary: Alexander Lightwood swore on the angel he would never hurt Magnus Bane so what happens when he does? Will the curse kill him? Will Magnus save Alec or will he leave him to die from his own promise?
1. Chapter 1

**So I was in the middle of writing my other story A Kittens Wish and I got this idea. What happens when a shadowhunter swears on the angel and then breaks it? What if Alec swore to never hurt Magnus? I was like "Yes! I could totally make a story out of that!" But to be honest I have no idea where this is going or even if Alec should die or not so please review or PM me and let me know what you think, want to happen, or if I should continue it! This is really angsty because i'm in an angsty mood and I honestly don't know how this story could be happy or fluffy but I hope you like it anyway!**

**Warning: This story contains spoilers for City of Lost Souls (I think)**

Alec collapsed to his knees in the subway, tears streaming down his face as his reason to live walked away from him. How could he be so stupid!? Going behind Magnus's back to talk to Camille, how could he break Magnus's trust like that!? Though one part of his mind whispered that Magnus should have listened. Should have opened up more and trusted him. Magnus knew everything there was to know about him yet Alec didn't know anything from his past other than what happened to his parents.

To be honest it hurt. It hurt that Magnus didn't open up to him, didn't let him explain that he never wanted Magnus to be a mortal in the first place, but the thing that hurt the most was the fact that Magnus trusted Camille more than Alec. Camille had told Magnus that Alec was seeing her to take away his immortality, and Magnus believed it instantly not even thinking for a minute that maybe Alec was seeing Camille for a different reason. Yet even though Magnus shared the blame just as much as him he couldn't help but hate himself and what he did to Magnus. He hurt him. He swore to Magnus that he would never hurt him and he did.

Alec gasped and clutched at his chest where it felt like his heart was splitting in two. This wasn't right. Yes, he felt so heartbroken about Magnus he couldn't see how he would be able to keep going but his heart literally _hurt_. The pain was excruciatingly painful, so much it was hard to keep breathing. Gasping for air that wasn't filling his lungs Alec started to see black spots in his vision. Maybe this was what drowning felt like.

Alec clawed at his chest trying to make the unbearable pain stop until finally Alec's vision went black and he collapsed to the dirty floor of the abandoned subway tunnel.

* * *

Alec groaned and rolled over. His whole body ached and felt just plain _wrong_, especially his heart, and his senses where clouded with the smell antiseptic and bleach. Was he in the infirmary? Slowly, he forced open his eyes that felt as if they had been glued shut and looked around, trying not to move his pounding head.

His assumption was affirmed as he looked around the white walls and hard beds of the institute infirmary. In the chair beside his bed sat his sister who was currently asleep with her head propped up by her hand and her black hair falling around her arms like a blanket. Worry lines where etched on her face and Alec frowned. What would make her so worried?

His mind was suddenly filled with memories of last night and Alec could barely hold back his tears. Him and Magnus where broken up. Alec forced a smile on his face that probably looked more like a grimace as Isabelle started to stir. She opened her eyes and they widened when she saw that he was awake. She was hugging him tightly in an instant as if she would never let go. Alec wrapped his arms around his sister trying not to show how much pain he was in.

Isabelle started rambling worriedly, still not pulling away from the hug. "Oh Alec, we where so worried! You said you would come over this morning at seven to train with Jace but you didn't come so we called Magnus and he didn't answer. We went to his apartment and he wouldn't answer the door either so Jace grabbed a sweater from you're room and put a tracking rune on it and it said you where in the abandoned subway and so we ran over there and you where laying on the floor passed out and breathing erratically! What happened!?" She said this in all one breath and Alec had trouble keeping up with her.

He hesitated. He really didn't want to tell her that Magnus and he had broken up, because it felt as if he said the words it would make it true. And Isabelle would of course want to kill Magnus or want to know what happened or both and Alec didn't want to explain that either. As for what happened to him, Alec didn't know himself and he didn't want to worry his siblings.

Isabelle pulled back from the hug and glared at him obviously reading his hesitation. "Alexander Gideon Lightwood, you are going to tell everything that happened right now, and I mean EVERYTHING. I want to know why you where at the subway, what happened, and why Magnus isn't talking to us, NOW."

Alec sighed. His sister wouldn't leave him alone until he told her everything and would know if he left anything out. He tiredly began to explain everything and prayed she wouldn't hate him when he was done.

**Wow. I think I just hurt myself writing that. I'm not entirely sure what should happen to him or what the side effects should be of breaking the promise or if he and Magnus should get back together so I would really appreciate it if you reviewed or PM me! I hope you liked it (Even though it was very angsty) XD**


	2. Chapter 2

**Hey guys! I apologize for taking so long to update my stories, I'm just nor really sure what to write next. I will try my best to update them all as soon as I can! is being weird at the moment so I apologize if the formatting is different or if there is a gap instead of a line break. There maybe may be quotes from the book so yeah, I obviously don't own anything! Don't sue me! XD Now none of you probably even read these author notes anyways so I'm just gonna skip to please review and let me know what you think!**

**Warning: There may be slight cussing **

Alec sat fidgeting, as his brother and sister looked at him. The expression on their faces clearly expressed they thought he was an idiot. Suddenly Isabelle sighed. "Alec, you need to talk to Magnus and explain why you where going to Camille and talk to him about it." Alec opened his mouth quickly to protest but his brother cut him off. "Seriously bro, you really need to talk to him about it. If nothing else you can have closure."

Alec shook his head frantically. "No, I cant." Isabelle opened her mouth to try to convince him to talk to Magnus again but Alec kept rambling. "I _cant _Isabelle. It won't do anything. He won't forgive me. I don't _deserve _to be forgiven. I tried to shorten his life. I cant talk to him." Isabelle looked at him sadly. "Ok Alec. I won't try to make you talk to him but you can't be sure he won't forgive you." She got up, squeezed his hand and walked out of the infirmary, stilettos clicking on the white tiles.

Jace looked at him and gave him a comforting smile he rarely ever showed. "I'm always here if you need to talk bro." He stood up, slapped him on the back, and walked out of the infirmary door. Alec sat staring at the bed and rubbed at his aching chest with his hand. He sighed. He was exhausted. Alec pushed the covers back and stood up slowly on shaking legs. His stomach felt fluttery and Alec held onto the desk. He took a deep breath, let go of the desk, and slowly made his way out of the infirmary to his room. He had never been so glad that his room was on the first floor.

When he got to his room he collapsed on his bed and buried himself under the blue covers. He pulled his knees up to his chest and wrapped his arms around his chest, finally allowing his tears to fall.

* * *

Alec awoke to an intense pain in his abdomen. He groaned and hurriedly threw back the covers and sprinted to his bathroom. He barely crouched over the toilet before he threw up. His throat burned as he vomited the contents of his stomach into the toilet. His stomach ached almost unbearably. After about a minute of this, the pain subsided, leaving Alec gasping for air.

When it looked like he wasn't going to keep throwing up he leaned back against the the wall and wiped the sweat from his brow with a shaking hand. He waited until his breathing slowed and pushed himself up from the floor. He flushed the toilet and leaned against the sink for support. Alec turned on the faucet and rinsed his mouth out with a handful of cold water, wrinkling his nose at the acrid taste in his mouth.

He looked in the mirror and winced at his reflection. He was as white as a sheet, his black hair that was plastered against his forehead with sweat a startling contrast against his pale skin. His eyes where a dull blue and had dark circles under them. He looked like a walking corpse. Alec splashed the cold water against his face, hoping it would bring some life back into him.

He made his way back into his room and just as he collapsed on his bed with relief, someone knocked on his door. Alec groaned. Jaces voice drifted through the door. "Alec, open up. I brought you some soup. You need to eat _something_. You haven't come out of there in thirteen hours and Isabelle is considering coming up here and force feeding you her mystery stew."

Alec looked at the clock on his desk and his eyes widened in surprise. It _had _been thirteen hours. How had he been sleeping so long, especially after he had just woke up? Alec got up from his bed reluctantly and opened his door. Even though he was far from hungry, he really did not want to have to eat Isabelle's stew.

Jace was standing in front of him holding a steaming bowl and his eyes grew with concern when he saw Alec. "You look awful." He stated. "Gee, thanks." Alec muttered sarcastically as he took the offered bowl from his brother's hands. "Seriously though, you can't just let yourself waste away, Alec. You need to get over him and move on."

Alec glared at him. "Move on? Move on!? How the hell am I supposed to _move_ on? The love of my life doesn't want anything to do with me anymore, Jace! What would you do if it was Clary, huh? I seem to remember when you two thought you where siblings and you where practically suicidal, going on hunts alone and trying to get yourself killed! And Clary didn't even hate you! So don't you dare stand there and tell me that I need to _move_ on!" Alec spat out and slammed his door in Jace's face.

He stomped over to his bed, sat the bowl on his table and flopped down on the bed angrily. How could they expect him to move on? They love of his life didn't want to ever see him again. He was probably already over him and sleeping with some other black haired blue eyed boy! Though the last words they spoke to each other still rang in his ears and he knew it wasn't true.

_"Aku cinta kamu." "What does that mean?" It means I love you. Not that that changes anything." _

But how could it not change anything? Wasn't love enough of a reason to at least try? Alec sighed and picked up the bowl of soup, blowing on it to cool it off. It wouldn't do any good to starve himself.

He sipped at his soup slowly as his thoughts filled with all the memories of him and Magnus and the memories that they would never make.

* * *

**Sorry this chapter is so short guys! But it's better to have a short chapter sooner than a long one a lot later, right? XD I hope you liked it!**


	3. Chapter 3

**I can't stop writing this story! I really should be working on my other's but I have no idea for what I want to write next for them and I love writing this one! **

**NeonAngel: I totally love you're idea about Alec not being able to be loved again but I think that would be too painful to write! XD I'm glad you liked the last chapter and didn't think the emotions where overdone! Sometimes I go overboard and write my stories ****_Too _****angsty! I know, don't you just love caring Jace? :3 **

**AKA Annabeth: I'm glad you liked the summary! I'm not very good at them but I try my best! XD I hope you like the rest of my story just as much!**

**There will most likely be a lot of time skips in this chapter because Alec is going to be doing research in books and I don't want to have to right what the book says! XD I hope it doesn't bother you too much! Anyway, I hope you all like this chapter! Please review or PM me and let me know what you think!**

* * *

Alec tossed and turned on his bed restlessly. He was too exhausted to do much more than rest but he felt too sick and feverish and uncomfortable to fall asleep. He felt freezing cold but his skin was hot to the touch. He was drenched in sweat and his teeth where chattering violently. Finally deciding a warm shower might help, he got up and padded into the bathroom.

Alec peeled his clothes of his sticky skin and jumped when he saw something black out of the corner of his eye. He turned around and looked into the mirror and his eyes widened in horror. He touched his chest with a shaking hand. Right where his heart was, was a dark black spot. Black veins were leading out from the dark spot and spreading outward. He sat there staring at it for what could have been a minute or an hour, thousands of possibility's running through his head.

What was it? What was wrong with him? Was that part of everything else that was wrong with him? Was he going to die?

He ran his hands through his hair in frustration. His brain was foggy and he couldn't think straight, not to mention he was starting to panic. He took a deep breath and let it out slowly. It wouldn't do any good to freak out. Deciding a shower might help him think, he turned on the water and stepped into the warm spray. He pressed his forehead against the cool tiles as the warm water ran over him.

He didn't know how long he stood there in the same position, head resting against the white tiles. Eventually he shut the water off and stepped out onto the fluffy blue mat Isabelle had insisted placing in his bathroom. He grabbed a towel hanging from the rack on his wall and dried off. Just when he wrapped the towel around his waist and was about to get some clothes from his room, an excruciating pain appeared in his stomach and he stumbled to the toilet, throwing up again.

Even when he vomited the entire contents of his stomach into the toilet he still sat there retching. The pain subsided slowly and he coughed violently, the coughing making his burning throat hurt even worse. He gasped, breathing uneven. When his pulse slowed and he was sure he had the strength to stand, he got up slowly. Horror rose inside him when he was about to flush. There was blood in the toilet.

He held his head in his hands and tried not to hyperventilate. He took a deep breath and let it out slowly, repeating this routine five or six times. He _really _needed to figure out what was going on.

* * *

Alec ran his fingers over though worn books in the library. After he got dressed, he had decided he needed to figure out what was happening to him as soon as possible and the best way to go about that was to search the books in the library but where did he even start? The library was _huge._ There was three levels full of books and there was not one crevice that wasn't filled with shelves packed full of them. Even the tables, Hodge's old desk, and some of the chairs where stacked with books.

He groaned in frustration. He didn't even know what he was looking for! Did someone put a spell on him? A curse? Did he have some type of rare disease? Did he get poisoned by a demon and didn't notice? Alec decided he should start with a book on shadowhunter illnesses and diseases first. He remembered Hodge had a book somewhere on the second story by the library doors. He had read parts of it to them when he was teaching them about shadowhunter illnesses. Could he have forgotten something important mentioned in it?

Alec climbed up on one of the ladders and swung sideways, making it slide to the right, near the doors. He inspected the worn covers, searching for a gray book. He didn't remember much more than that. He pulled the book out triumphantly when he found it. After climbing down the ladder, he plonked himself in his favorite old chair and gently opened the book.

* * *

Alec rubbed at his eyes tiredly, trying to stay awake. He glanced at his watch and his head fell against the back of the chair in annoyance. He had been reading this book for _eight_ _hours**.**_ How was he ever going to find out what was wrong with him if it took this long to read _one_ book!? Magnus would probably know, he thought depressingly.

Alec dragged himself out of the chair and walked to his bedroom. Once he closed the door he walked over to his closet and grabbed a more comfortable shirt he could sleep in. Just as he pulled his shirt over his head and threw it to the floor, someone knocked on his door loudly and barged in. He froze. "Alec you need to-" Isabelle started as she stormed into her room but was cut off by a gasp when she saw his chest.

Isabelle rushed over to him. "Alec what happened?! Are you ok?! Have you been poisoned by a demon!? Are you hurt!? I'll go get my stele!" Alec caught her hand as she spun around to run out and find her stele. He looked at her sadly. "Izzy, I don't think a stele will help. I don't know what's wrong with me, I've been researching shadowhunter illnesses and diseases in the library and I finished the whole book Hodge read to us but I couldn't find anything that matched my symptoms."

"What are you're symptoms!?" Isabelle asked desperately. "Well... My heart has been hurting, my body feels weird, I've been throwing up and the last time I threw up blood, and I go through different stages. Sometimes my stomach will hurt really bad, other times I feel like I have a really bad fever and shake a lot, and I feel exhausted."

"You've been throwing up _blood!?"_ Isabelle asked shrilly. "Hold on, I'm going to get Jace!" She exclaimed as she ran toward the door. "Isabelle wait-" Alec started but was cut off by the door slamming closed. Alec flopped onto his bed and groaned.


End file.
